Environmental change impacts on the C- and N-cycle of European forests: a model comparison study

• Published in: Biogeosciences
• Main Authors: CAMERON David, VAN OIJEN Marcel, WERNER Christian, BUTTERBACH-BAHL K., GROTE R, HAAS E, HEUVELINK Gerard, KIESE Ralf, KROS Hans, KUHNERT M, LEIP Adrian, REINDS Gert Jan, REUTER Hannes I., SCHELHAAS M. J., DE VRIES W., YELURIPATI Jagadeesh
• Language: English
• Published: COPERNICUS GESELLSCHAFT MBH 2013
• Subjects: Northern Sweden
• Online Access: https://publications.jrc.ec.europa.eu/repository/handle/JRC80922; http://www.biogeosciences-discuss.net/9/11041/2012/bgd-9-11041-2012.html; https://doi.org/10.5194/bg-10-1751-2013

Forests are important components of the green-house gas balance of Europe. There is considerable uncertainty about how predicted changes to climate and ni-trogen deposition will perturb the carbon and nitrogen cycles of European forests and thereby alter forest growth, carbon sequestration and N2 O emission. The present study aimed to quantify the carbon and nitrogen balance, including the exchange of greenhouse gases, of European forests over the period 2010–2030, with a particular emphasis on the spatial variability of change. The analysis was carried out for two tree species: European beech and Scots pine. For this pur-pose, four different dynamic models were used: BASFOR, DailyDayCent, INTEGRATOR and Landscape-DNDC. These models span a range from semi-empirical to complex mechanistic. Comparison of these models allowed assess-ment of the extent to which model predictions depended on differences in model inputs and structure. We found a Eu-ropean average carbon sink of 0.160 ± 0.020 kgC m −2 yr −1 (pine) and 0.138 ± 0.062 kgC m −2 yr −1 (beech) and N2 O source of 0.285 ± 0.125 kgN ha −1 yr −1 (pine) and 0.575 ± 0.105 kgN ha −1 yr −1 (beech). The European av-erage greenhouse gas potential of the carbon sink was 18 (pine) and 8 (beech) times that of the N2 O source. Carbon sequestration was larger in the trees than in the soil. Carbon sequestration and forest growth were largest in central Eu-rope and lowest in northern Sweden and Finland, N. Poland and S. Spain. No single driver was found to dominate change across Europe. Forests were found to be most sensitive to change in environmental drivers where the drivers were limiting growth, where changes were particularly large or where changes acted in concert. The models disagreed as to which environmental changes were most significant for the geographical variation in forest growth and as to which tree species showed the largest rate of carbon sequestration. Pine and beech forests were found to have differing sensitiv-ities to environmental change, in particular ...